Nicron #39 19 июня 1997

Железо

Iron - K155 series chips.

           "Iron" ... logic!


(C) KLIM


  Logic gates AND, OR and NOT, which we talked
earlier, in "pure form" is not made. How
application received various combinations, for example: AND-NOT,
NOR, AND-OR-NOT, and others. Their symbols are composed of
Legend of constituent elements.

  Integrated circuits have a rectangular plastic or
ceramic package with a pin, curved at a right angle.
Typically, the number of conclusions 14, seven on each side. 
Rooms conclusions are measured from the tags placed on the case 
against clockwise when viewed from above the housing of the 
chip. 

  K155 series chips, which we are going to consider,
consist of biopolyarnyh transistors. For zero signal level
take the voltage is less than or equal to 0.4 V, and for the 
unit signal - the voltage from 2.4 V to 5 V. The voltage supply 
for them equal to +5 V with a tolerance of + / - 5%.


  Basic element of integrated circuits is the basis for
construction of various logic circuits and flip-flops, as
He used a logical element AND-NOT or NOR. For example,
Products K155LA3 and K155LA8 contain four elements AND-NOT to
two inputs each.



  If, for example, the inputs of 1.2 or 4.5 unit served
signals, with 3 or 6 zero signal is removed, with other
combinations of input signals on output will be logical
unit. Similarly, there are three other schemes logic
an AND-NOT. The difference in these chips is that
K155LA8 integrated circuit designed for high currents
loads needed for reliable indicators.
Connecting directly to the outputs of IC K155LA3
LED and miniature incandescent lamps is not recommended,
although this is sometimes done in amateur designs.
K155 series chips have one important feature:

  If the input signal is not, it is tantamount to filing
these single signal. Zero input is perceived chip
only when it is connected to a source of low-
voltage. Accordingly, the output chips and K155LA3
K155LA8 signals must be logic 0 if the inputs are not
the signals.

  Figures 3 and 4 show, respectively, an OR element,
derived from three elements, and NAND chips K155LA3 and
RS-flip-flop based circuits K155LA8.7



  The next time we'll be working in an integrated flip-flops
performance.